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GRB050502B optical and X-ray light curves

GRB050502B optical and X-ray light curves. Paulo Afonso Working with: Jochen Greiner, Elena Pian, Aybüke Yoldaş - with the collaboration of Daniele Malesani, Stefano Covino, Thomas Krühler Schloss Ringberg meeting 21-2-2008.

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GRB050502B optical and X-ray light curves

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  1. GRB050502B optical and X-ray light curves Paulo Afonso Working with: Jochen Greiner, Elena Pian, Aybüke Yoldaş - with the collaboration of Daniele Malesani, Stefano Covino, Thomas Krühler Schloss Ringberg meeting 21-2-2008

  2. Bright x-ray flares are superposed on underlying power-law decay (solid line). Possible jet break at ~ 1 day (100 000 sec) postburst. From Burrows et alia, 2005 Paulo Afonso - Schloss Ringberg, 21-2-2008

  3. Conspicuous characteristics • X-Ray flare has ~ same energy (~9x10-7 erg/cm2, 0.3-10 keV) as the prompt emission observed by BAT (~8x10-7 erg/cm2, 15-350 keV). This was never observed before! • Early fainter afterglow than other XRT-detected, but rapid brightening several minutes later • Bumpiness continues at late-time, before decaying back to preflare fluxes (Burrows et al, 2005) Paulo Afonso - Schloss Ringberg, 21-2-2008

  4. Explanations/models • Continued activity in the internal engine is required – not associated with the afterglow external shock, because: • Rise and decay times of flare are very fast • The afterglow started already before the flare (same time decay index before and after flare) • Later bumpiness not so easy to explain: maybe internal engine & afterglow shock together (Falcone et al., 2006) Paulo Afonso - Schloss Ringberg, 21-2-2008

  5. But things are more complex: flares, plateaus, chromatic breaks. (Figure from Panaitescu, 2007) Paulo Afonso - Schloss Ringberg, 21-2-2008

  6. Work in progress: reduce data again, for better optical photometry Preliminary light curve: Data points from TNG and ANU. Note steep decay at t~ 1 day in the I-Band. Time correlation with end of 2nd X-ray flare? Paulo Afonso - Schloss Ringberg, 21-2-2008

  7. Final science image (combining 2 images) TNG 1for I band.Problems:bad pixels,fringing effects Paulo Afonso - Schloss Ringberg, 21-2-2008

  8. TNG 3 final science image for I band. Glare: due to problem in automatic flat procedure. Paulo Afonso - Schloss Ringberg, 21-2-2008

  9. TNG 1 Vs. TNG 3 – fringes “disappear” because of higher number of combined science images. Normally a higher number is required for successful removal of fringes. We are looking for more data in archives of TNG right now. Paulo Afonso - Schloss Ringberg, 21-2-2008

  10. TNG2 I band – fringes removed with just 2 individual images Paulo Afonso - Schloss Ringberg, 21-2-2008

  11. TNG3 I band – even with many individual images, removal of fringing seems now more effective Paulo Afonso - Schloss Ringberg, 21-2-2008

  12. TNG2 I band without fringes: very first crude photometry – not so bad! In this image:22.33 +/- 0.27former image: 22.10 +/- 0.16 Paulo Afonso - Schloss Ringberg, 21-2-2008

  13. Next steps – ongoing work: • Fringe effects removal/reduction on TNG1 • Photometry of TNG3 – very faint object!!? • Photometry of TNG2 R band • Use of further TNG archive images to make better fringe patterns Paulo Afonso - Schloss Ringberg, 21-2-2008

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